Discrepancies in the behavior of my cBot on different cTrader platforms(main server's and brokers')

Dear sirs,

I back tested my cbot on both Brocker's Topfx ctrader and main servers' ctrader, with exactly same parameters and same identical logic and conditions, I witnessed astonishingly that target profit reached on Brockers' ctrader platform and stopped cbot while on servers' ctrader did not stop when same profit reached, and servers' ctrader behavior seemed different from brokers' encountering losses. what could be the reason?